(d) Advise shipping to proceed with caution or to divert from 

 estabUshed routes in areas not recently scouted, but in which the 

 presence of ice was considered possible or probable on the basis of old 

 reports and estimated drift; 



(e) Recommend unscheduled shifts in the North Atlantic Track 

 Agreement tracks when advisable; and 



(/) Decide when to commence and susjjend ice patrol operations at 

 Argentia. 



Estimates of ice drift and mortality rates were obtained by the use 

 of the current charts constructed from data collected on the four 

 oceanographic surveys made during the ice season by U. S. C. G. 

 cutter Evergreen in critical parts of the ice patrol area/ the sea 

 surface isotherm charts prepared semimonthly from the sea surface 

 temperatures reported by shipping, and the wind (hita furnished by 

 the United States Fleet Weather Central at Argentia. The current 

 charts and isotherm charts for the 1954 ice season are shown in figures 

 15, 16, 18, 19, and 1 to 9, respectively. 



The 1954 ice season in the Grand Banks area was marked by a re- 

 turn to fairly average berg conditions after three successive light ice 

 years. Three hundred and twelve bergs drifted south of latitude 

 48° N. during 1954 as compared with 6 in 1951, 14 in 1952, 56 in 

 1953, and 404, the average annual numl)er for the period 1900-53. 

 The most southerly position reached by any berg was 39°51' N., 

 48°30' W., on 1 June. With respect to field ice the season was 

 briefer than normal, and the pack did not reach south of latitude 

 47° N. at any time. 



In the Gulf of St. Lawrence and St. Lawrence River, the pack ice 

 broke earlier than usual, and the fii'st ship reached Montreal via 

 Cabot Strait on 30 March. By 22 April all the gulf and river routes 

 were clear except the Strait of Belle Isle. 



The pack concentration in the Strait of Belle Isle was reduced suf- 

 ficiently by 11 June to permit the passage of ice-protected vessels. 

 By 22 June the pack concentration was low enough for unprotected 

 vessels to proceed through the strait with caution, and to the east of 

 the strait Track G was clear of field ice. However, many bergs were 

 scattered throughout the strait and along Track G as far east as the 

 1,000-fatliom curve at that time and until the end of the ice season. 



Between the first of the year and 7 March, several bergs were re- 

 ported lying over 300 miles to the east and southeast of Cape Farewell. 

 This unusual situation made for an unexpected hazard in the more 

 northerly Atlantic shipping lanes and prompted an oceanographic 

 survey to be made in the area to the east and southeast of Cape 

 Farewell. Results of the survey are set forth elsewhere in this 

 bulletin. 



Details of the ocpanographic program aro ^dveii elsewhere in this l)ulletin. 



